[Antimicrobial activity of cefodizime against fresh clinical isolates]

In order evaluate antimicrobial activities of cefodizime (CDZM), minimum inhibitory concentrations (MIC's) of CDZM and other control drugs were determined against various clinical isolates, that were sent to our center from nation-wide medical institutions or were isolated and identified in our laboratory from various specimens of infected patients. The followings are a summary of the results: 1. Bacterial species with no or few strains resistant to cephems including CDZM included Streptococcus pyogenes, Haemophilus influenzae, Citrobacter diversus, most of Klebsiella pneumoniae and Proteus mirabilis. Some strains of Klebsiella oxytoca were resistant to cephems increases in beta-lactams resistant Streptococcus pneumoniae and cephem resistant Escherichia coli seemed likely. Among Citrobacter freundii, Enterobacter spp., Serratia marcescens, Proteus vulgaris, Morganella morganii and Providencia spp. belonging to a category of so-called "mildly toxic bacteria", high portions of the strains examined were resistant to cephems including CDZM and these strains were also resistant to new quinolones, thus they showed multiple drug resistance. 2. MIC90's of CDZM against Streptococcus spp., H. infleunzae, Moraxella subgenus Branhamella catarrhalis, E. coli, Klebsiella spp. and P. mirabilis, frequently found in daily treatment of infections, were less than < or = 0.025 to 1.56 micrograms/ml. This indicates that CDZM would be expected to have enough antibiotic activity in infections caused by above mentioned bacteria. However, cautions are needed in the treatment of infections by beta-lactam resistant S. pneumoniae, cephem resistant E. coli and cephem resistant K. oxytoca with CDZM. 3. Among the above mentioned "mildly toxic bacteria", many multiple drug resistant strains exist. Therefore, we evaluated an usefulness of concomitant use of CDZM with aminoglycosides in the treatment of infections by these bacteria, using other reports which indicates the usefulness in vitro and in vivo. 4. Antibacterial activities of CDZM we observed in this study seem to indicate that CDZM concentrations in infected areas are maintained at above MIC levels for relatively long periods of time.